1. Field of Invention
This invention relates generally to material handling and more particularly to a load ejector for the excavator bucket of a back hoe that operates automatically responsive to positioning of the excavator bucket.
2. Background and Description of Prior Art
Back hoe excavator buckets and similar buckets on other digging machines pivotally mounted on a supporting beam for motion between somewhat vertical digging positions and somewhat horizontal unloading positions have long been known, are widely used in earth moving and are somewhat standardized in their structure and configuration. These excavator buckets in general have an open front that is pivoted to a vertical orientation to move horizontally through the earth to collect a load of material in the excavator bucket which is then moved to a disposition site the bucket is pivoted to a horizontal orientation, so that the bucket orifice opens downwardly, to allow gravity to remove material therefrom. This operation is effective, however, only with loose granular non-cohesive materials such as particulated rock, sand, dry soils, small debris and the like.
If material being excavated is adhesive to adhere to the surface of the carrying excavator bucket, it often may not be removed from the excavator bucket solely by force of gravity and requires other means to remove it. This problem is exacerbated if the material is also cohesive. The problem of cohesiveness is common with soil materials consisting of, or containing, wet clay, various finely particulated soil materials or debris containing wet clay or other material that is both cohesive and adhesive. This problem in the past often has been dealt with by a machine operator or another workman manually loosening the material in the excavator bucket to allow removal by the forced gravity acting thereon. Another common solution has been to maintain the excavator bucket in a horizontal dumping position, move it over some resistive surface and attempt to mechanically pound the excavator bucket on the resistive surface to lessen the adhesion and cohesion of the material mass therein by reason of inertia created by the pounding action. These solutions however are labor intensive, time consuming, not cost efficient and the machine activated pounding process may cause damage to the excavator bucket or the mechanism associated with it.
These problems have heretofore been recognized and responsively various less damaging and less time consuming mechanical methods for removing cohesive and adhesive material from excavator buckets have been devised. None of such methods, however, have completely or adequately resolved the problems, at least for all or a substantial number of the excavator buckets of modern commerce and the various materials causing adhesion and cohesion. The instant mechanism seeks to resolve various of these remaining problems.
One earlier solution for material removal from excavator buckets provided an extractor plate, commonly of curvilinear configuration to fit against the inner surface of the excavator bucket back, that is mechanically moved outwardly between the excavator bucket sides in the containment chamber while the excavator bucket is in a horizontal, downwardly opening dumping position to aid the gravity force in removing material in the bucket chamber therefrom. With such mechanism, material in the excavator bucket remains as cohesive as it was when initially moved into the excavator bucket, or more so, and remains as adhesive to the extractor plate as it was to the bucket inner surface. This solution is not efficiently operative and, if it is operative at all, generally requires substantial power in addition to gravity force to remove material from the excavator bucket. By reason of the substantial power requirement for operation of the extractor plate, many such mechanisms have been powered by new hydraulic linkages that were not originally provided with a back hoe and, if mechanically activated, such linkages have required complex power magnifying linkages which have not proven to be well or efficiently operative, have been short lived and have required substantial maintenance.
In recognition of these problems some later more modern excavator bucket cleaning systems have provided cleaning members of lesser area than the area of the back of the excavator bucket to be cleaned. Such known devices have commonly used multiple band-like elements to move over and along portions of the excavator bucket interior. These multiple band-like elements generally have been configured to fit against portions of the inner surface of the excavator bucket and while diverging therefrom pivot to release material in the bucket. Such multiple band-like devices have generally been complex, have been adapted for use only with particular excavator buckets and in use have not proven to be particularly efficient or effective in removing all or substantial amounts of contained material from the excavator buckets they service. Various such systems have continued to suffer the mechanical problems associated with the large plate devices, have not been easily retrofitable on pre-existing machines they service and have required complex mechanical linkages that use substantial force to accomplish their motion. The complexity of such more modern cleaning systems generally has required such modification of excavator buckets, their ordinary mechanical linkages, or both as to require the ejector mechanism to be created during the manufacture of the excavator bucket and generally make impractical the retroactive installation of the systems in existing extractor buckets and their moving mechanisms, at least by ordinarily skilled mechanics in the art.
In contradistinction the instant ejector mechanism provides relatively narrow ejector arms that are carried in laterally spaced adjacency on an interconnecting ejector arm shaft journaled between the ejector bucket sides for pivotal motion along each side of the excavator bucket and away from the lower portion of the bucket back. This structure provides ejector arms of substantially less surface area than the bucket back that in their motion scrape material from the lower portion of the bucket sides. The ejector arms yet provide quite sufficient area to eject material from the excavator bucket when in unloading position, but not enough area to allow adhesion of any substantial amount of material in the excavator bucket.
The mounting and positioning of the ejector arms allow simple mechanical innerconnection of the ejector arm shaft carrying them with a powering arm that extends forwardly through the bucket back to communicate with excavator bucket pivoting structure to provide automatic operation of the ejector mechanism responsive to the angular position of the excavator bucket relative to the support arm carrying it and powering by the hydraulic system that powers the pivoting motion of the excavator bucket. This simplified ejector mechanical structure allows retrofitable installation of the instant ejector system in many, if not most, of back hoe mechanisms of modern day commerce with only minimal modification that may be readily accomplished by relatively unskilled workmen with only such knowledge and ability as is common to operators and mechanics who normally deal with back hoes in their routine operation and maintenance.